Pulp magazines had a pretty big impact on American popular culture, one of the strangest such "impacts" was the creation of the Lemuria mythos by Richard Shaver, whose byline is seen in the above image.
His stories of Lemuria and hollow earth has spawned a fringe movement where the belief is that Lemuria, Atlantis and "the motherland of Mu" all really existed and some claim to have encountered modern-day inhabitants of these lost continents.
Read on for this odd tale ... (orriginally from http://www.disorganization.com/danbala/History/Shaver.html)

Richard Sharpe Shaver
Until Richard Sharpe Shaver came along, nearly all nineteenth- and twentieth-century hollow-earth proponents spoke of the inner world's inhabitants as members of an advanced, benevolent race whom it would be desirable for human beings to meet and befriend. Shaver, however, had another story to tell. Shaver technologized hell.

In September 1943, in Chicago, Amazing Stories editor Ray Palmer read a letter from a Barto, Pennsylvania, reader who claimed to know of an ancient alphabet from Lemuria, a continent said to have sunk in the Pacific Ocean thousands of years ago, taking a mighty civilization with it. Palmer reprinted the alphabet in the January 1944 issue, and soon he and the reader, Shaver, were corresponding regularly.

Shaver alleged that for years evil creatures the Vhujunka, also known as "deros"-short for "detrimental robots" (who were not robots as the term is ordinarily understood but "robots" in the sense of being slaves to their passions)-had tormented him. Vhujunka were the degenerate remnants of the "Titans," the people of Lemuria, who 12,000 years ago were forced to escape into great caverns under the earth to avoid deadly radiation from the sun. (Some Titans, however, stayed on the surface, adjusted, and became the present human race. Others fled to distant planets.) Vhujunka-demons in all but name and close to it even there-were sadistic idiots who had access to the advanced Titan technology, which they used to increase sexual pleasure during the orgies to which they were addicted. They also used the machines in marathon torture sessions on kidnapped surface people and also on the "teros" (integrative robots, who were not robots but good Titans who, though vastly outnumbered, were fighting the deros); they also employed the machines to cause accidents, madness, and other miseries in the world above the caves.

Soon Amazing and its companion pulp Fantastic Adventures were filled with exciting and terrifying tales of the underworld. Most of these stories bore Shaver's by-line, but Palmer was writing them. The first, "I Remember Lemuria!", all 31,000 words of it, appeared in Amazing Stories March 1945 issue, and in the introduction Shaver told readers of his vivid memories of life as Mutan Mion, who lived many thousands of years ago in Sub Atlan, one of the great cities of ancient Lemuria!"

A flood of letters crossed Palmer's desk, some from individuals who claimed they, too, had met with the deros and barely lived to tell Amazing about it. Chester S. Geier, one of the magazine's regular contributors, started the Shaver Mystery Club as a way both of handling the mail and of "investigating" the "evidence" for the deros. Palmer and Shaver had caused quite a stir.

Not all readers were happy about it, however. Many were furious; convinced that some sort of swindle was afoot, they feared that the Shaver mystery would make all science-fiction fans look like fools or worse. By 1948 their protests led Ziff-Davis, Amazing Stories parent company, to order the series stopped.

After co-founding Fate with Curtis Fuller in 1948, Palmer left Ziff-Davis and moved to tiny Amherst, Wisconsin, to produce his own magazines, notably Flying Saucers and Mystic (later Search), which regularly featured Shaver material. In 1961 he started The Hidden World, a series of magazines in trade-paperback format, and over the next three years reprinted Shaver's original articles and ran new contributions from a diminishing band of enthusiasts.

Shaver died in Arkansas in November 1975, Palmer in Florida two years later.